Sylva J15 Build Blog: Engine fit and cooling system

Engine fit and cooling system

The engine, Ford Sigma/Puma 1.7 vvti, was refreshed by Sitek in Rosyth earlier in the year. The engine wiring loom and and ECU was removed from the donor Puma. So a lot of uncertainty was in my mind at this point in the build. A chap called Steve from the Westfield Sports Car club gave me a hand to do the install. The fuel system and tank are my own design which just added to the pile of things that could go wrong.

The install of the engine went smoothly enough, mainly as I did a trial install before having the chassis painted. Proceeded to connected up the fuel system and ECU, could not find the Vehicle Speed Sensor (VSS) anywhere but decided we would proceed anyway. Connected up the battery, to my amazement the PAT's LED started flashing, I was so excited I did not even decode what it was telling me, my only defence was it looked very like the code my Ford Connect gives when the key is inserted.

Moving rapidly on, I put fuel in the tank and turned the key. The fuel pump ran and one of the fuel filter connectors at the rear started pissing fuel all over the floor. The leaking connector was one I made up quickly the previous day so I could retain the original Ford quick connect engine bay fuel pipes. Adding some PTFE tape to the 1/4NPT union did the business and the engine started, wow!

As the cooling system did not exist I thought it best to switch off the engine, the only problem was the engine remained on despite my efforts with the ignition key. Quick thinking, Steve pulled the connector off the coil pack, obviously he had done this before as I was very slow to react. I was thinking of pulling the battery terminal but I suspect that was probably the wrong thing to do. As it was 9:30 PM and we had been at it all day (at least 12 hours) it was time to call it a day.

The list of problems at this point:

* Needs cooling system.
* Needs oil pressure light and gauge connected.
* Fault in the wiring keeping the engine on, power hold relay cct suspected in the Battery Fuse Box.
* No Alternator warning light on dash (never came on).
* Needs throttle linkage

cooling system

Of all the problems I guess a cooling system is number one. So I posted a note on the Lowcost forum asking what to order up in terms of pipes, bends etc. I did not get any answers that suggested a way forward that I liked so I decided to order up:

6 x 32mm x 90deg
3 x 32mm x 45deg
1 x 1m x 32mm
1 x 32 x 32 x 25mm T piece Silicone
1 x 1m x 22mm
1 x 1m x 10mm
1 x 1m x 16mm
1 x 3m length of 32mm x 16gauge alloy tubing
1 x 3m Length 16mm alloy tubing
1 10" high power fan
That lot came to well over £200 mostly from Rally design but I have not thrown away any parts and the system is fully connected.

I fabricated the Polo radiator mounting very like the suggestion from Jeremy except the Fan I mounted on a removable alloy plate with lots of hoses in it. The radiator is easily removed also with 6 x ss machine screws.

Oil pressure switch and gauge

The oil pressure gauge came with a sensor but I rapidly discovered I needed an 2 way oil adaptor to make both the switch and oil pres gauge work at the same time. All the standard adaptors gave no room for both the switch and sensor when connected at the back of the Sigma engine. I did find a site offering a flexible hose + 2 connection points for 1/8NPT devices but it also assumed an 1/8NPT hole in the engine. I made up an adaptor using a 1/4 NPT brass F-F and silver soldered the 1/8NPT bit on the end after turning the thread off the 1/8NPT part. I used a 1/8NPT pressure switch instead of the original Ford one.

Wiring faults

It is not surprising I had a fault, in fact of all the scenarios I could envisage the engine running on fault was not that difficult I hoped. It took about 4 hours in the end to track down. I separated the engine wiring loom from the original Puma wiring and rewired the Battery Junction box throwing away all the unwanted wiring connection crap that you etc on a modern car. I could bore you with the details but two solder joints and a couple of bits of heat shrink solved all. The trick was to trace all the wires from the ignition RUN cct to the power hold relay. The mistake was somewhat obvious but not at the time of course. The Alternator light had the wrong supply on one end.

Remaining problems

The engine has now run successively for about half an hour with no major problems

* Engine temperature sensor falls off readily, needs new connector.
* No Vehicle Speed Sensor (don't know what impact this has yet)
* Extra throttle return spring required, will not return rapidly to tickover.
* Temp gauge sensor needs changed to the one matching the gauge.

Drive shafts

The next problem is to send the drive shafts away and get them friction welded. The nearside shaft is 40mm too long and the offside shaft 40mm too long. I have boxed them up and sent them off to a chap called Paul Sowersby at Driveshaft Solutions in Gateshead.